authd: Placement of User into Incorrect Group
CVE-2026-6970 is a high-severity placement of user into incorrect group vulnerability in authd from Canonical, with a CVSS 4.0 base score of 7.3 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 0.6.4, 0.6.1ubuntu0.1 as the first without the flaw, so updating authd to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.11% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update authd to 0.6.4 or 0.6.1ubuntu0.1, whichever matches your release line, or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Canonical | authd | 0.6.0 up to, but not including, 0.6.4; 0.6.1 up to, but not including, 0.6.1ubuntu0.1 | 0.6.4, 0.6.1ubuntu0.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- HighSerious loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA (ubuntu.com).
Official description
authd prior to version 0.6.4 contains a logic error in primary group ID assignment that can lead to local privilege escalation. When a user's primary group ID (GID) differs from their UID, either because the account was created with authd prior to version 0.5.4 or because the primary group was manually changed via the `authctl group set-gid` command, and the user's identity provider record is updated, authd incorrectly resets the user's primary group ID to their UID upon next login. This causes newly created files and directories to be owned by the wrong group, causing denial of service issues, and potentially granting unintended access to other local users and allowing local privilege escalation.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Placement of User into Incorrect Group
The product or the administrator places a user into an incorrect group.
More Placement of User into Incorrect Group vulnerabilities (CWE-842)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in authd
- 8.5 High severity
Recent Placement of User into Incorrect Group vulnerabilities
- 8.4 High severity
- 8.8 High severity
- 7.8 High severity
- 7.2 High severity
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